3.5 Filename extensions
You can use any filename extension for the input file, but if you do not
use the recommended extension for a particular format you may need to
manually specify the output format; for details, see Invoking lilypond-book.  Otherwise, lilypond-book automatically
selects the output format based on the input filename’s extension.
| extension | output format | 
 | 
| ‘.html’ | HTML | 
| ‘.htmly’ | HTML | 
| ‘.itely’ | Texinfo | 
| ‘.latex’ | LaTeX | 
| ‘.lytex’ | LaTeX | 
| ‘.lyxml’ | DocBook | 
| ‘.tely’ | Texinfo | 
| ‘.tex’ | LaTeX | 
| ‘.texi’ | Texinfo | 
| ‘.texinfo’ | Texinfo | 
| ‘.xml’ | HTML | 
If you use the same filename extension for the input file than the
extension lilypond-book uses for the output file, and if the
input file is in the same directory as lilypond-book working
directory, you must use ‘--output’ option to make
lilypond-book running, otherwise it will exit with an error
message like “Output would overwrite input file”.